Benzophenone-3,4,3{40 ,4-tetracarboxylic acid diimides of 3,5-dialkyl-4-hydroxyphenylsubstituted amines

ABSTRACT

Benzophenonetetracarboxylic acid diimides of 3,5-dialkyl-4hydroxyphenylsubstituted amines of this invention effectively stabilize organic materials against the effects of heat and oxygen. The diimides of this invention are prepared by reacting the appropriate 3,5-dialkyl-4-hydroxyphenylsubstituted amine with benzophenone-3,4,3&#39;&#39;,4&#39;&#39;-tetracarboxylic acid dianhydride or diimide. An example of this class of stabilizers is N,N&#39;&#39;-bis(3,5di-t-butyl-4-hydroxybenzyl)3,4,3&#39;&#39;,4&#39;&#39;-tetracarboxylic aciddiimide.

Uitd States ?atent 91 fiexter May 22, 1973 BENZOPHENONE-3,4,3',4-

TET CARBOXYLIC ACID DHMIDES 0F 3,5-DIALKYL-4- HYDROXYPHENYLSUBSTITUTEDAMHNES Inventor:

Martin Dexter, Briarcliff Manor, NY.

Assignee: Ciba-Geigy Corporation, Ardsley,

Filed: Oct. 4, 1971 Appl. No.: 186,560

U.S. Cl ..260/326 N, 252/402, 252/403,

260/45.8 N, 260/3463 llnt. Cl. ..C07d 27/52 Field of Search ..260/326 NReferences Cited UNITED STATES PATENTS 9/1966 Ellis et a1 ..260/326OTHER PUBLICATIONS Marvel et al., J. Am. Chem. Soc. Vol. 80, 6,600-6,604(1958).

Primary Examiner-Alex Maze] Assistant Examiner-Joseph A. NarcavageAtt0rneyKarl F. Jorda and Nestor W. Shust [57] ABSTRACT 3 Claims, NoDrawings 1 2 BENZOPHENONE-3,4,3',4-TETRACARBOXYLIC nide and reduction ofthe resultant dialkylhydroxyphe- ACID DIIMIDES OF nyl acetonitrile tothe amine. The amine wherein y is 33,5-DIALKYL-4-HYDROXYPHENYLSUBSTITUTED can be prepared by reducing3,5-dialkyl-4-hydroxyphe- AMINES nyl-propylnitrile with lithium aluminumhydride to 7 yield the corresponding amine. The nitrile can be pre-DETAILED DESCRIPTION pared according to the method described in US. Pat.

This invention relates to novel benzophenone tetra- No. 3,121,732wherein the appropriate dialkylhydroxycarboxylic acid diimidederivatives of 3,5-dialkyl-4- phenol is reacted with acrylonitrile. The3,5-dialkyl-4- hydroxyphenylsubstituted amines which are useful ashydroxybenzyl dialkyl amine of formula III can be prestabilizers fororganic polymeric materials which are 10 pared as described by E.P.Previc et al., Industrial and subject to thermal and oxidativedeterioration. The Engineering Chemistry, Vol. 53, NO. 6, Page 469, Junecompounds of this invention are represented by the for- 1961. mula: Thebenzophenone-3,4,3,3'-tetracarboxylic acid di- 9 9 0 R1 3 x l 1I yH-.yN\ /N- c,my @-on l R9 C ('3 R2 wherein each of R and R is the same ordifferent imide can be prepared by methods described in U.S.

(lower) alkyl group of from one to four carbon atoms; Pat. No.3,275,651.

and y has a value of from 0 to 3. The compounds of this invention arestabilizers of or- Illustrative examples of (lower) alkyl groups of fromganic polymeric material normally subject to thermal one to four carbonatoms which are represented by R and oxidative deterioration. Materialswhich are thus and R are methyl, ethyl, propyl, isopropyl, butyl andstabilized include synthetic organic polymeric subt-butyl. The preferredgroups are methyl, isopropyl and stances such as vinyl resins formedfrom the polymert-butyl. ization of vinyl halides or from thecopolymerization of The compounds of the formula 1 wherein y is 0, 2vinyl halides with unsaturated polymerizable com: and 3, can be preparedby reacting a 3,5-dialkyl-4- pounds, e.g., vinylesters, a,B-unsaturatedketones, hydroxyphenylsubstituted amine of the formula a,B-unsaturatedaldehydes, and unsaturated hydrocarbons such as butadienes and styrene;poly-a-olefins such as polyethylene, polypropylene, polybutylene, and

the like, including copolymers of poly-a-olefins; polyurethanes andpolyamides such as poly-hexamethylene uoflwP adipamide andpolycaprolactam; polyesters such as R2 H polyethylene terephthalate;polycarbonates; polyacetals; polystyrene, polyethyleneoxide;polyisoprene;

40 polybutadene; and copolymers such as those of high wherein impactpolystyrene containing copolymers of butadi- R1 and R2 are as definedPreviously, and y is 0,2 and ene and styrene and those formed by thecopolymer- 3, with y acid ization of acrylonitrile, butadiene and/orstyrene. dianhydride in an inert solvent such as dichlorobenzene Igeneral, one or mom f h bili f h presat reflux temperatures entinvention are employed in amounts, in toto, of from The Compounds offormula 1 wherein y is 1 can be about 0.005 to about 5 percent by weightof the com- P p y reacting 3,5dialkyl'4hydroxybenzyl' position to bestabilized. A particularly advantageous dialkylamlne of the formularange of the present stabilizers is from about 0.05 to about 2 percent.The preferred range is particularly efu fective in polyolefins such aspolypropylene and poly- R ethylene. Ir0 O CH N These compounds may beincorporated in the polymer substance during the usual processingoperations,

m R m for example, by hot-milling, extrusion compounding and the like.The polymers may be produced as films,

wherein fibers, filaments, hollow-spheres and the like. The heat R and Rare as defined previously and R is an alkyl stabilizing properties ofthese compounds advantagroup such as methyl or ethyl, withbenzophenonegeously stabilize the polymer against degradation durt yacid diimide, in an inert 6O ing such processing at the hightemperatures generally vent such as dimethyl formamide at approximatelyencountered.

120 C. The stabilizers employed in this invention can also be The3,5-dialkyl-4-hydroxyphenylsubstituted amines used in combination withother stabilizers or additives. wherein y is 0 can be prepared asdescribed in US. Pat. Especially useful co-stabilizers aredilauryl-B-thiodi- No. 3,198,797. The amine, when y is 2 can beprepropionate and distearyl-B-thiodipropionate. pared, for example,through chloromethylation of a The following formula representsco-stabilizers dialkylphenol as described in US. Pat. No. 2,838,571,which are in certain instances very useful in combinafollowed bytreatment with sodium or potassium cyation with the stabilizers of thisinvention:

wherein R is an alkyl group having from six to 24 carbon atoms; and m isan integer from 1 to 6. The above co-stabilizers are used in the amountof from 0.01 to 2 percent by weight of the organic material, andpreferably from 0.1 to 1 percent.

Other antioxidants, antiozonants, thermal stabilizers, ultraviolet lightabsorbers, coloring materials, dyes, pigments, metal chelating agents,etc., may also be used in the compositions in combination with thestabilizers of the invention.

The following are presented to further illustrate the present inventionwithout introducing any limitation thereto.

EXAMPLE 1 N ,N '-Bis( 3 ,5-di-t-butyl-4-hydroxybenzyl)Benzophenone-3,4,3,4' tetracarboxylic acid diimide To 200 ml. ofdimethylformamide were mixed 16.0 g ofbenzophenone-3,4,3',4'-tetracarboxylic acid diimide (0.05 mole) and 27.6g of 3,5-di-t-butyl-4- hydroxybenzyl dimethyl amine (0.1 mole). Thereaction mixture was heated under a nitrogen atmosphere at 120 to 125 Cfor 6 hours. After cooling, the reaction mixture was poured into water.The material obtained was extracted with ether. The ether extract waswashed with dilute l-lCl and then with water. Upon evaporation of theether, an amorphous solid was obtained. The product was triturated withhot petroleum ether after which it was recrystallized twice from aqueousacetone. The product obtained has a melting point of 218 to 221 C.

Analysis for C l-l N O Calculated: C, 74.58; H, 6.93; N,3.7O

% Found: C, 74.34; l-l,6.89; N,3.54

In a similar manner, by substituting3-methyl-5tbutyl-4-hydroxybenzyl-dirnethyl amine for3,5-di-tbutyl-4-hydroxybenzyl-dimethyl amine there is obtained N, N'-bis-(3-methyl-5-tbutyl-4-hydroxybenzyl)benzophenone 3,4,3',4tetracarboxylic acid diimide.

EXAMPLE 3 N ,N '-Bis( 3 ,5-di-t-butyl-4-hydroxyphenyl)benzophenone-3,4,3,4'-tetracarboxylic acid diimide The reaction flask ischarged with 1 1.05 g (0.05 moles) of 4-amino-2,6-di-t-butylphenol, 8.0g (0.025 mole) of benzophenone-3,4,3',4-tetracarboxylic acid dianhydrideand 100 ml of O-dichlorobenzene. The reaction mixture is heated toreflux until the imidization is completed. After cooling, the mixture isfiltered and washed with petroleum ether. The filtrate is dried andrecrystallized from aqueous acetone acid and filtered, after which it iswashed with acetic acid and dried.

By substituting an equivalent amount ofB-(3,5-di-tbutyl-4-hydroxyphenylethyl )amine for 3 ,5-di-t-butyl-4-hydroxyphenylamine in the above procedure, the corresponding N,N'-bis[B-(3,5-di-t-butyl-4-hydroxyphenyl )ethyl] benzo-phenone-3,4,3,4-tetracarboxylic diimide is obtained.

In a similar manner, by substituting an equivalent amount of3-(3,5-di-t-butyl-4-hydroxyphenyl)propylamine for3,5-di-t-butyl-4-hydroxyphenylamine in the above procedure, thecorresponding N,N-bis[3-3,5-dit-butyl-4-hydroxy-phenyl)propyl]benzophenone- 3,4,3',4-tetracarboxylic acid diimide is obtained.

EXAMPLE 4 Unstabilized polypropylene powder (Hercules Profax 6501) wasthoroughly blended with 0.2 percent by weight of N ,N '-bis( 3,5-di-t-butyl-4- hydroxylbenzyl )benzophenone-3 ,4,3 ',4 tetracarboxylicdiimide.

Also prepared were samples of polypropylene containing 0.1 percent byweight of the same stabilizer and 0.3 percent by weight ofdistearylthiodipropionate (D- STDP). The blended materials were thenmilled on a two-roll mill at 182 C for 10 minutes, after which time thestabilized polypropylene was sheeted from the mill and allowed to cool.

The milled polypropylene sheets were then cut into pieces and pressedfor 7 minutes on a hydraulic press at 218 C, 2,000 pounds per squareinch pressure. The resulting sheets of 25 mil thickness were tested forresistance to accelerated aging in a forced draft oven at 150 C. Theresults are set out in Table 1 below:

TABLE 1 Oven Aging at 150 Additive(s) Hours to Failure 0.2% ofN,N'-bis(3,5,di-tbutyl-4-hydroxybenzyl)benzophenone-3,4,3',4'-tetracarboxylic acid diimide 0.1% ofN,N'-bis(3,5-di-t-butyl- 4-hydroxybenzyl)benzophenone-3,4,3',4'-tetracarboxylic acid diimide 0.3% DSTDP UnstabilizedPolypropylene "distearylthiodipropionate (a synergist for phenolicanti-oxidants) EXAMPLE 5 Pellets (500 g) of unstabilized nylon-6,6(Zytel 101 Dupont) are placed in a Kitchen Aid Mixer. With mixing asolution of 2.5 g (0.5 percent) ofN,N'-bis(3,5-dit-butyl-4-hydroxyphenyl )benzophenone-3 ,4 ,3 ',4-tetracarboxylic acid diimide in 20 ml of acetone is added slowly to thenylon pellets. The stabilized pellets are dried at C at 1mm for 4 hours.

The polyamide formulation is extruded at 600 F through a '/4 inch dieinto a rod which is water cooled and chopped into pellets. A 56 inchBrabender extruder, equipped with a nylon screw, is used. The pelletsare dried at 80 at 1mm for 4 hours.

The dried pellets are pressed into 5 X 5 X 0.005 inch films at 290 and350 psi for 3 minutes. The mold is transferred quickly to a water-cooledpress and maintained at 350 psi for 2 to 3 minutes.

Samples (2.2 g) of compression molded nylon-6,6 films are aged in an aircirculating rotary oven at 150 C for various time periods. The viscosityof a 11 percent formic acid solution of aged and unaged polymer samplesare determined at 25 C. Stabilizer effectiveness is judged by thepercent retention of specific viscosity, color-formation, and weightretention after oven aging The stabilized polyamide has betterviscosity, color retention, and substantially less weight loss than apolyamide which is unstabilized after oven agmg.

Stabilized polyamide compositions are prepared in a similar manner asabove with the following stabilizers:

a. 0.5 percent of N,N-bis(3,5-di-t-butyl-4-hydroxybenzyl)benzophenone-3,4,3,4- tetracarboxylic acid diimide b. 0.5percent of N,N-bis( 3-methyl-4-t-butyl-4- hydroxybenzyl )benzophenone-3,4,3 ,4- tetracarboxylic acid diimide c. 0.5 percent ofN,N'-bis[2-(3,5-di-t-butyl-4- hydroxypheny)ethyl]benzophenone-3,4,3,4-tetracarboxylic acid diimide.

EXAMPLE 6 A quantity of SBR emulsion containing 100 g of rubber (500 mlof cold SBR type 1500) previously stored under nitrogen, is placed in abeaker and stirred vigorously. The pH of the emulsion is adjusted to10.5 with a 0.5N NaOH solution.

To the emulsion is added 50 ml of 25% NaCl solution. A 6% NaCl solutionwhich has been acidified with HCl to a pH 1.5 is added in a thin streamwith vigorous stirring. When pH 6.5 is reached, the rubber begins tocoagulate and the addition is slowed down in orderTo maintain uniformagitation. The addition of the acidic 6% NaCl solution is terminatedwhen a pH 3.5 is reached. The coagulated crumb-rubber slurry at pH 3.5is stirred for one-half hour.

The coagulated rubber is isolated by filtration through cheese cloth,and rinsed with distilled water. After three subsequent washings withfresh distilled water, the coagulated rubber is dried, first at 25 mm Hgand finally to constant weight under high vacuum 1 mm.) at 4045 C.

The dried rubber (25 g) is heated under nitrogen at 125 in a Brabendermixer and to this is added with mixing 0.125 g (0.5 percent) ofN,N-bis[3-(3,5-di-tbutyl-4-hydroxyphenyl) propyl] )benzophenone-3,4,3',4-tetracarboxylic acid diimide. The composition is mixed for 5minutes after which it is cooled and compression molded at 125 C into 5X 5 X 0.025 inch plaques.

The plaques are placed on aluminum sheets and heated in a circulatingair oven at C for up to 96 hours. The viscosity of a 0.5 percent toluenesolution of aged and unaged rubber samples are determined at 25 C.Stabilizer effectiveness is judged by the percent retention of specificviscosity, color formation and gel content after oven aging. Thestabilized rubber has better viscosity, color retention and less gelcontent than the rubber which is unstabilized after oven aging.

Similar results are obtained when N,N-bis(3,5-di-tbutyl-4-hydroxybenzyl)benzophenone-3 ,4,3 ,4 tetracarboxylicacid diimide is used in place of the above mentioned stabilizer in therubber composition.

EXAMPLE 7 A composition is prepared comprising linear polyethylene and0.1 percent by weight ofN,N'-bis(3,5-di-tbutyl-4-hydroxybenzyl)benzophenone-3 ,4,3 ,4tetracarboxylic acid diimide. This composition resists discoloration atC longer than one which does not contain the stabilizer.

What is claimed is:

1. A compound of the formula:

0 Q C ll l5 l R.

l 01 0 N C C R ll 11 O 0 wherein each of R and R is the same ordifferent (lower) alkyl group of from one to four carbon atoms; and yhas a value of from O to 3.

2. The compound according to claim 1 wherein R and R is tertiary butylor methyl.

3. The compound according to claim 2 which is N,N-'-bis-3,5-di-t-butyl-4-hydroxybenzyl)benzophenone-3,4,3',4'-tetracarboxylic acid diimide.

2. The compound according to claim 1 wherein R1 and R2 is tertiary butylor methyl.
 3. The compound according to claim 2 which isN,N''-bis-3,5-di-t-butyl-4-hydroxybenzyl)benzophenone-3,4,3'',4''-tetracarboxylic acid diimide.